function preNumUser = plotView(utMatrix)
    index=find(utMatrix(:,3)==4);
    utMatrix=utMatrix(index,:);
    preNumUser=[]
    for i=1:31
        tem=[i,size(find(utMatrix(:,4)==i))];
        preNumUser=[preNumUser;tem];
    end
    plot(preNumUser(:,1),preNumUser(:,2));
end

